Class: Grade 8, General Science Unit: Volcanoes Topic: Igneous Rock Formation
Instructional Objectives:
Define igneous rock, extrusive & intrusive igneous rock, and crystallization.
Analyze the size of crystals that form from a solution under different cooling conditions.
Introduction:
Now that students have learned the three classes of rocks and the minerals which aggregate to form them, I will teach the students the different ways that igneous rocks form. I will explain that by learning how temperature effects the formation of crystals, we develop the skills to analyze how a sample of igneous rock formed.
I will say, “Today we will be looking at the way crystals form at different temperatures. This is important because scientists use this knowledge when they analyze volcanic rocks. For example, if a rock has very small crystals or none at all, scientists can tell that the rock cooled off very quickly and had to of been formed outside of a volcano. Being able to apply this knowledge provides scientists with another way to understand volcanoes and their eruptions. By the end of today’s lesson, all of you will be able to make conclusions about how a rock formed based on its crystal size. You will then be given the chance to grow your own crystals by making rock candy.”
To begin this class discussion, I will pass around two different kinds of igneous rock (one intrusive and one extrusive) and ask the students for their observations. I want them to observe that one rock has smaller crystals than the other rock. I will then ask the students "What factor(s) do you think could contribute to the different crystal sizes in these two rock samples?" I will then tell the students we will be investigating this today.
Activities & Assignments:
10 minutes: Using book, define mineral, rock, and igneous rock in notebooks.
10 minutes: Class discussion and notes on intrusive and extrusive igneous rocks and their textures (due to crystallization).
15 minutes: Examine 4 igneous rock samples. Create table to place observations about color, mineral composition, and texture based on crystal size.
20 minutes: Demonstration - Investigating Crystallization - using magnesium sulfate, crystals are grown quickly in a cold water bath and slowly on their own. Demonstrates crystals that form intrusively and crystals that form extrusively.
17 minutes: Students pair off to make rock candy. Each pair is given a cup, stick, water, and sugar. Put together and leave in room until rock candy forms (few days to a week).
Materials Needed:
Textbooks
Igneous rock samples
hot pot
250mL beaker
glass stirrer
food coloring
petri dishes
materials for chilling petri dishes
safety goggles
magnesium sulfate
sugar & water
plastic cups
wooden sticks
Resources for Lesson:
O'Donnell, C. (2000). Science and Technology Concepts for Middle Schools; Catastrophic Events. Burlington, North Carolina: Carolina Biological Supply Company.
Unit: Volcanoes
Topic: Igneous Rock Formation
Instructional Objectives:
Introduction:
Now that students have learned the three classes of rocks and the minerals which aggregate to form them, I will teach the students the different ways that igneous rocks form. I will explain that by learning how temperature effects the formation of crystals, we develop the skills to analyze how a sample of igneous rock formed.
I will say, “Today we will be looking at the way crystals form at different temperatures. This is important because scientists use this knowledge when they analyze volcanic rocks. For example, if a rock has very small crystals or none at all, scientists can tell that the rock cooled off very quickly and had to of been formed outside of a volcano. Being able to apply this knowledge provides scientists with another way to understand volcanoes and their eruptions. By the end of today’s lesson, all of you will be able to make conclusions about how a rock formed based on its crystal size. You will then be given the chance to grow your own crystals by making rock candy.”
To begin this class discussion, I will pass around two different kinds of igneous rock (one intrusive and one extrusive) and ask the students for their observations. I want them to observe that one rock has smaller crystals than the other rock. I will then ask the students "What factor(s) do you think could contribute to the different crystal sizes in these two rock samples?" I will then tell the students we will be investigating this today.
Activities & Assignments:
Materials Needed:
Resources for Lesson:
O'Donnell, C. (2000). Science and Technology Concepts for Middle Schools; Catastrophic Events. Burlington, North Carolina: Carolina Biological Supply Company.
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